This application claims the benefit of Korean Application No. 2001-3415 filed Jan. 20, 2001, in the Korean Patent Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to an optical disc drive, and more particularly, to an optical disc drive having an improved structure so that a slim optical disc drive is possible.
2. Description of the Related Art
In general, an optical disc drive such as a CD player or DVD player records information by emitting light onto a disc which is a recording medium or reproduces information by reading information from the disc. In a conventional optical disc drive as shown in FIG. 1, a tray 40 has a first receiving surface 41 for accommodating a disc 1 having a 120 mm diameter and a second receiving surface 42 for accommodating a disc (not shown) having a 80 mm diameter. The tray 40 moves into and out of a main frame 10 while carrying the disc. A pivoting sub-frame 20 is installed at the main frame 10. A base chassis 30 is supported on the sub-frame 20.
A turntable 32, on which the disc 1 carried by the tray 40 is placed, and an optical pickup 31 for recording information on the disc 1 or reproducing information therefrom while moving across the disc 1 are installed on the base chassis 30. A loading motor 11 drives the tray 40 to retract into and eject from the main frame 10 through a predetermined loading unit. Reference numeral 12 indicates a cam member having a cam groove (not shown) into which a cam protrusion 21 of the sub-frame 20 is inserted, for moving up and down the cam protrusion 21 according to the rotation of the loading motor 11. Thus, as the cam member 12 rotates, the cam protrusion 21 ascends and descends while moving along the trace of the cam groove. Accordingly, the sub-frame 20 pivots around a pivot axis passing through pins 22 supported by the main frame 10.
In the disc drive as shown in FIG. 1, where a disc 1 is placed on the tray 40 and the tray 40 enters the main frame 10, the cam member 12 is rotated and the sub-frame 20 pivots so that the disc 1 is placed on the turntable 32. Then, the turntable 32 rotates and the optical pickup 31 reproduces information recorded on the disc 1 or records new information thereon.
However, in the above conventional optical disc drive, since the cam protrusion 21 provided at the sub-frame 20 is directly inserted in the cam member 12 and thus the sub-frame 20 is moved up and down by the cam motion between the cam protrusion 21 and the cam member 12, the cam member 12 is required to be located at a position lower than the lowest position in which the cam protrusion 21 is located in a range that the sub-frame 20 pivots. That is, as shown in FIG. 2, to secure the elevation height of the turntable 32 according to pivot of the sub-frame 20, the cam member 12 inevitably occupies a space down at a lower position (h+h1) out of a pivot range (h) of the sub-frame 20. Thus, this pivot structure occupying a large space of the optical disc drive in height is considered to be an inappropriate structure considering a current trend in which products are made light and thin.
Another problem in making an optical disc drive slim is that, where an 80 mm disc is carried by being placed on the second receiving surface 42 of the tray 40, the disc is caught by a boss 32a of the turntable 32 so that the tray 40 may not be moved. For example, when the 80 mm disc placed on the turntable 32 is taken out, the sub-frame 20 is lowered and pivots to place the disc on the second receiving surface 42 of the tray 40 so that the tray 40 is taken out of the main frame 10. When the lowering height of the turntable 32 is too small in order to making an optical disc drive slim, the disc is caught by the boss 32a (FIG. 1) of the turntable 32 so that the tray 40 is not easily ejected from the main frame 10. Where the lowering height of the turntable 32 is too large, it is difficult to make an optical disc drive slim. Thus, there is a need to prevent the disc from being caught by the boss 32a while making the lowering height small.
In another conventional optical disc drive, a turntable or optical pickup is directly installed on the tray to realize a slim optical disc drive for notebook computers. However, in most cases, tray motions such as entering in or ejecting from the main frame are manually performed which inconveniences a user. Thus, an optical disc drive having a structure to solve the above problems is needed.
To solve the above problems, it is an object of the present invention to provide an optical disc drive having an improved structure which enables automatic tray loading and a slim optical disc drive.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and, in part, will be obvious from the description, or may be learned by practice of the invention.
According to the present invention, a disc carrying tray is supported by a main frame. A base chassis is pivotable with respect to the main frame and supports a turntable which rotates a disc. The turntable is common with a rotor of a spindle motor which drives the turntable.
The base chassis has a free end which is elastically coupled with a free end of a sub-chassis which also pivots with respect to the main frame. An optical pickup, which records information on and reproduces information from the disc, is mounted on the base chassis. A feeding unit moves the optical pickup in a radial direction of the disc to record information on and/or reproduce information from the disc. A tray loading unit retracts the tray into and ejects the tray from the main frame.
A cam member has a cam groove which is slidingly engaged with a cam protrusion on the sub-chassis. The cam member is operationally engaged with the tray loading unit to pivot the sub-chassis as the tray loading unit retracts the tray into or ejects the tray from the main frame. The sub-chassis pivots the base chassis to engage the turntable with the disc or to disengage the turntable from the disc.
A loading motor drives a gear rail on the tray loading unit via a loading gear. A cam gear, selectively engaged with the cam member, transfers the driving force of the loading motor to the cam member. The disc drive comprises a latch which prevents escape of the tray where the tray is retracted into the main frame. The latch comprises a hooking piece formed on the tray which engages an interference piece provided on the cam gear to block a return path of the hooking piece where the tray is retracted.
The feeding unit comprises a guide rail arranged at the base chassis along a radial direction of the disc and a lead screw installed parallel to the guide rail to be rotated and driven by a motor. A gear portion provided at one side of the optical pickup is coupled to the lead screw.
The tray comprises an outer surface and a first disc receiving surface. The first disc receiving surface is formed to be recessed from the outer surface and to accommodate a disc having a first diameter. A stepped portion connects the outer surface and the first disc receiving surface.
The tray further comprises an escape preventing unit which prevents the disc from escaping from the tray by pressing the disc placed on the first disc receiving surface against the stepped portion in a direction opposite the direction in which the tray retracts. A rotary lever is installed at the outer surface of the tray. An elastic member provides an elastic force to urge the rotary lever in a direction to push the disc against the stepped portion. A locking protrusion protrudes from the outer surface of the tray toward the rotary lever to prevent the disc from being pushed above the outer surface.
A second disc receiving surface is formed to be recessed from the first disc receiving surface for accommodating a disc having a smaller diameter than the disc which is accommodated by the first disc receiving surface. The second disc receiving surface is inclined such that a depth of the second disc receiving surface decreases in a direction in which the tray retracts into the main frame.
A plurality of receiving pads for supporting the bottom surface of a disc placed on the first disc receiving surface are installed at a boundary portion between the first and second disc receiving surfaces. The pads support the disc where the disc is placed on the first disc receiving surface and/or edge portions of the disc where the disc has the smaller diameter to prevent the disc having the smaller diameter from escaping from the second disc receiving surface.
First and second sensors which generate loading and unloading operation signals are mounted on the main frame. A knob on the tray operates the first sensor to start an ejection operation and a protrusion mounted on the mainframe operates the second sensor where the tray is completely ejected from the main frame. Where the tray is completely retracted into the main frame, the knob is pressed to generate a tray unloading operation signal. Where the tray is completely ejected from the main frame and the tray is pushed into the main frame, the switching protrusion operates the second sensor to generate a loading operation signal.